Infinitely variable change speed gears



- g- 1965 I F. G. DE BRIE PERRY 3,203,267

INFINITELY VARIABLE CHANGE SPEED GEARS Original Filed Aug. 17. 1960 2Sheets-Sheet 1 F 91 4545 5/ 47 54 fi 1965 F. 5. DE BRIE PEYRRYY3,203,267

INFINITELY VARIABLE CHANGE SPEED GEARS Original Filed Aug. 17. 1960 2Sheets-Sheet 2 //V VEN 70/? 9 :4 $410 1. n6. 414g 5 Lr/wm JMza aw!United States Patent M 3,203,267 INFINITELY VARIABLE CHANGE SPEED GEARSForbes George de Brie Perry, East Grinstead, Sussex, England, assignorto National Research Development Corporation, London, Engiand, a Britishbody corporate Continuation of application Ser. No. 50,151, Aug. 17,1960. This application Dec. 12, 1961, Ser. No. 160,694 Claims priority,application Great Britain, Aug. 19, 1959,

17 Claims. (Cl. 74-200) This application is a continuation of my UnitedStates patent application No. 50,151 filed August 17, 1960 nowabandoned.

This invention relates to infinitely variable change speed gears of thefriction type having coaxial first and second torus discs spaced apartand drivably connected by a plurality of rollers, and means to tilt theaxes of the rollers, which means comprises a cam and a plurality ofrockers all controlled by the cam, said rockers each being pivotallycarried by a torque reaction member of the gear to pivot about a pivotaxis such that the rocker senses the torque reaction of a roller and thesystem tends to balance the torque reaction of all the rollers.

According to the present invention, there is provided such aconstruction of infinitely variable change speed gear in which eachrocker has an arm extending into a cam slot in the cam with radialfreedom between the cam and the rocker arm and at least one of the camslots contains a guide member and is shaped to permit a relativemovement axially of the slot between the cam and the guide member and topermit relative rotation about the axis of the slot between the cam andthe guide member but to retain the guide member against relativemovement between the cam and the guide member at right angles to theaxis of the slot, and the end of the rocker arm extending into the slotis received with friction in the guide member.

According to a feature of the invention, the end of the rocker arm maybe received within a bore in the guide member and friction means may beprovided between the rocker arm and the guide member. Such frictionmeans may comprise a resilient member abutting and compressed betweenthe rocker arm and the wall of the bore and may for example be a metalspring member embracing the rocker arm and received within acircumferential slot in the rocker arm.

In constructions wherein the end of the rocker arm is received within acylindrical bore in the guide member, a further feature of the inventionprovides that the rocker arm may have a portion which fits thecylindrical bore and be otherwise relieved so as to permit tiltingbetween the rocker arm and the guide member in at least one direction.

According to yet another feature of the invention the gear may furthercomprise further friction means opposing relative axial motion betweenthe rocker and the cam. In some constructions adopting this feature, theguide member may be mounted to move with the rocker arm relative to thecam and the further friction means may comprise a resilient memberabutting and compressed between the guide member and the cam. Such aresilient member can be a metal spring member embracing the guide memberand received within a slot in the guide member.

According to yet another feature of the invention, the cam slot andguide member may be cylindrical with the guide member fitting within thecam slot.

One embodiment of the invention will now be de scribed by way of examplewith reference to the accompanying drawings, of which:

3,203,267 Patented Aug. 31, 1965 FIGURE 1 is an elevation showing achange speed gear,

FIGURE 2 is an elevation of part of the rocker gear and cam employed inthe change speed gear of FIG- URE 1,

FIGURE 3 is a scrap section through the end of a rocker arm and adjacentparts,

FIGURE 4 is a section on the line 4-4 of FIG- URE 3,

FIGURE 5 is a section on the line 5-5 of FIG- URE 2,

FIGURE 6 is a section on the line 6--6 of FIG- URE 2,

FIGURE 7 is a section similar to FIGURE 6 but of a modifiedconstruction, and

FIGURE 8 is a scrap section similar to FIGURE 3, but of a modifiedconstruction.

In this embodiment the gear comprises two inwardly facing first torusdiscs 45 mounted on and driven by a drive shaft 25, a double outwardlyfacing second torus disc 47 connected by a drum 48 to an output shaft 49and two assemblies of rollers 51, roller carriers 53 and rocker gearprovided one between each first torus disc and the second torus disc.Each assembly comprises three rollers having their centres spaced aroundan axis substantially conciding with the axis of the drive shaft.

Each rocker 21 is mounted to pivot on a torque-reaction member 52 of thegear and has a rocker arm 22 which extends into a cam slot cut in arocker cam 23 mounted on a rocker cam sleeve 24 which surrounds thedrive shaft 25 with radial clearance and limited axial and radialfreedom of movement relative to the drive shaft. The rocker cam sleeve24 is connected to a spider ring 61 at one end thereof. This spider ringforms part of a control means connected to move the rocker cam 23 aboutits axis in a manner well-known in the art, and more fully illustratedand described in the US. patent to Hayes 2,123,006 granted July 5, 1938.7

Each cam slot 26 contains a guide member 27 which has a bore 28extending transversely of the axis of the cam slot 26 and the end 29 ofeach rocker arm 22 is received within the bore 28 in a guide member 27.

The cam slots 26 are circular in section normal to their axis i.e. thedirection in which they extend and the guide members 27 are cylindricaland fit in the cam slots 26. Each guide member 27 has a circumferentialslot 31 extending around it (see FIGURE 6) from the ends of the bore anda C-shaped corrugated spring element 32 is received within thecircumferential slot 31 so that it embraces the guide member 27 whileleaving unobstructed the mouth of the bore facing out from the mouth ofthe cam slot.

The amplitudes of the corrugations of the spring member are such that,when it is unstressed, the crests of the corrugations project beyond thesurface of the guide member. Thus the spring element has to be stressedin order to insert it into the cam slot and thereafter is compressedbetween the guide member 27 and the wall 33 of the cam slot 26 so thatit generates friction when the cam 23 moves relative to the guide member27.

The end 29 of each rocker arm which is received in the bore 28 of theguide member has a cylindrical land 34 :at its tip and a recess 35bounded at one end by the cylindrical land 34 and .at the other end bythe shank 36 of the rocker arm. The shank 36 of the rocker arm isrelieved so that it is elliptical in cross-section and the depth of theland '34 is such that the end of the rocker aam can tilt in thedirection of the minor axis of the ellipse relative to the guide member.

A corrugated spring ring 37 is received in the recess 35 of the rockerarm .and the corrugations are of an amplitude such that the crests ofthe corrugations stand proud of the cylindrical surface of the land whenthe spring is unstressed. When the spring is received in the bore 28 ofthe guide member, the spring 37 is compressed between the rocker arm andthe wall of the bore and thus causes friction to be generated if therocker arm moves relative to the guide member along the bore.

' One result of using the present invention in constructions ofinfinitely variable change speed gear, is that the friction generated bythe spring members damps out any tendency which there may be to huntwhen the rocker gear adjusts itself to equalize the torque transmittedby the rollers of the infinitely variable change speed gear. In someconstructions this result may be obtained satisfac- .torily by causingfriction when the rocker arm moves radially relative to the cam and itwill be appreciated that, for instance, in gears having diametricallyopposed rollers, it may be suificient to generate friction between onlyone rocker arm and the cam.

It will also be appreciated that in the embodiment above described, thekind of springs and the material from which they are made should bechosen with regard tothe service which they have to perform. Forinstance, if the gear is oil lubricated, it is desirable tor the springs.to be metal springs. If however the possibility of oil reaching thespring elements can be excluded, then the springs could be in the formof O-sectioned rubber rings.

It will be appreciated that a number of modifications can be madewithout departing from the scope of the invention. Two suchmodifications are illustrated in the drawings. In that illustrated inFIGURE 7 the recess for the spring 31 which embraces the guide member 27is formed in the cam 23 instead of being formed in the guide member.

Again, as mentioned above, an actual form of spring employed can bechosen with a view to its best suiting the service which it has to carryout. For instance, for small gears a circlip as shown at 41 in FIGURE 8is satisfactory instead of the corrugated springs above described.

I claim:

1. An infinitely variable change speed gear of the friction type havingcoaxial first and second torus discs spaced apart, a plurality ofrollers drivably connecting the torus discs, a torque reaction memberand means to tilt the axes of the rollers, which means comprises a camand a plurality of rockers connected with the rollers and all controlledby the cam, said rockers each being pivotally carried by the torquereaction member to pivot about a pivot axis such that the rocker sensesthe torque reaction of a roller and the said means tends to balance thetorque reaction of all the rollers characterised in that each rocker hasan arm extending into a cam slot in the cam with radial freedom betweenthe cam and the rocker arm and in that at least one of the cam slotscontains a guide member which is shaped to permit a relative movementaxially of the slot between the cam and the guide member and to permitrelative rotation about the axis of the slot between the cam and theguide member but to retain the guide member against relative movementbetween the cam and the guide member at right angles to the axis of theslot, and in that the end of the rocker arm extending into the slot isreceived with friction in the guide member.

2. An infinitely variable change speed gear of the friction type havingcoaxial first and second torus discs spaced apart, a plurality ofrollers drivably connecting the torus discs, a torque reaction memberand means to tilt the axes of the rollers, which means comprises a camand a plurality of rockers connected with the rollers and all controlledby the cam, said rockers each being pivotally carried by the torquereaction member to pivot about a pivot axis such that the rocker sensesthe torque reaction of a roller and the said means tends to balance thetorque reaction of all the rollers characterised in that each rocker hasanarm extending into a cam slot in the cam with radial freedom betweenthe cam and the rocker arm and in that at least one of the cam slotscontains a guide member which is shaped to permit a relative movementaxially of the slot between the cam and the guide member and to permitrelative rotation about the axis of the slot between the cam and theguide member but to retain the guide member against relative movementbetween the cam and the guide member at right angles to the axis of theslot, and in that the guide member is formed with a bore in which isreceived the end of the rocker arm, and friction means are providedbetween the rocker arm and the guide member.

3. In an infinitely variable change speed gear of the friction typecomprising a pair of inwardly facing torus discs and a plurality ofrollers drivably connecting the torus discs, means to tilt the axes ofthe rollers, which means include:

(a) a cam having a plurality of cam slots,

(b) a plurality of rockers connected to the rollers and each having arocker arm; the said rocker arms engaging respectively in the cam slots,

(c) in at least one cam slot, a guide member retained against movementat right angles to the axis of the slot but movable relative to the camslot axially of the slot and about the axis of the cam slot; the guidemember having a bore therein in which is received one of the said rockerarms, and

(d) a resilient member abutting .and being compressed between the rockerarm and the wall of the bore.

4. In an infinitely variable change speed gear of the friction typecomprising a pair of inwardly facing torus discs and a plurality ofrollers drivably connecting the torus discs; means to tilt the axes ofthe rollers, which means include:

(a) a cam having a plurality of cam slots,

(b) .a plurality of rockers connected to the rollers and each having arocker arm; the said rocker arms engaging respectively in the cam slots,

(c) in at least one cam slot, a guide member retained against movementat right angles to the axis of the slot but movable relative to the camslot axially of the slot and about the axis of the cam slot; the guidemember having a bore therein in which is received the end of one of thesaid rocker arms which has a circumferential slot, and

(d) a spring embracing the rocker arm and being received within thecircumferential slot, the said spring being compressed between the saidrocker arm and the wall of the bore.

5. In an infinitely variable change speed gear of the friction typecomprising a pair of inwardly facing torus discs and a plurality ofrollers drivably connecting the torus discs; means to tilt the axes ofthe rollers, which means include:

(a) a cam having a plurality of cam slots,

(b) a plurality of rockers connected to the rollers and each having arocker arm; the said rocker arms engaging respectively in the cam slots,

(c) in at least one cam slot, a guide member retained against movementat right angles to the axis of the slot but movable relative to the camslot axially of the slot and about the axis of the cam slot; the guidemember having a cylindrical bore therein in which is received one of thesaid rocker arms which said one rocker arm has a portion which fits thecylindrical bore of the guide member and is otherwise rclieved so as topermit tilting between the rocker arm and the guide member in at leastone direction, and

(d) friction means between the rocker arm and the guide member.

6. An infinitely variable change speed gear of the friction typecomprising a pair of inwardly facing torus discs; a plurality of rollersdrivably connecting the torus discs; and means to tilt the axes of therollers, which means include:

(a) a cam having a plurality of cam slots,

(b) a guide member in each cam slot, said guide member being retainedagainst movement at right angles to the axis of the slot but beingmovable relative to the cam slot axially of the slot and about the axisof the cam slot; the guide members each having a bore therein,

(c) a plurality of rockers connected to the rollers and each having arocker arm; the said rocker arms being received respectively in saidbores, and

(d) a plurality of resilient members respectively abutting and beingcompressed between a rocker arm and the wall of the bore in which it isreceived.

7. In an infinitely variable change speed gear of the friction typecomprising a pair of inwardly facing torus discs and a plurality ofrollers drivably connecting the torus discs; means to tilt the axes ofthe rollers, which means include:

(a) a cam having a plurality of cam slots,

(-b) a plurality of rockers connected to the rollers and each having arocker arm; the said rocker arms engaging respectively in the cam slots,

(c) in at least one cam slot, a guide member having a bore therein inwhich is received one of the said rocker arms, and

(d) a resilient member abutting and being compressed between the rockerarm and the wall of the bore.

8. An infinitely variable change speed gear as claimed in claim 1comprising friction means opposing relative motion between the rockerand the cam.

9. An infinitely variable change speed gear as claimed in claim 8wherein the guide member is mounted to move with the rocker arm relativeto the cam and the friction means comprises a resilient member abuttingand compressed between the guide member and the cam.

10. An infinitely variable change speed gear as claimed in claim 9wherein the resilient member is a spring member embracing the guidemember and received within a slot in the guide member.

11. An infinitely variable change speed gear as claimed in claim 1wherein the cam slot and guide member are cylindrical with the guidemember fitting within the cam slot.

12. An infinitely variable change speed gear of the friction typecomprising:

(a) coaxial first and second torus discs spaced apart,

(b) a plurality of rollers drivably connecting the torus discs,

(c) a cam movable about the axis of the torus discs and movable radiallyrelative to the said axis,

(d) a plurality of rockers operatively connecting the cam to the rollerswhereby the cam may control the rollers,

(e) control means connected to the cam to move it about the said axis,and

(f) damping means connected to the cam to dampen radial movement of thecam relative to the said axis.

13. An infinitely variable change speed gear of the friction typecomprising:

(a) coaxial first and second torus discs spaced apart,

(b) a plurality of rollers drivably connecting the torus discs,

(c) a torque reaction member,

(d) a cam movable about the axis of the torus discs and movable radiallyrelatively to the said axis,

(e) a plurality of rockers operatively connected to the rollers andhaving respectively rocker arms, the inner ends of which are connectedto the cam with radial play, and

(f) a plurality of friction means respectively connecting the cam to theinner ends of the rocker arms.

14. An infinitely variable change speed gear as claimed in claim 13wherein the cam is provided with a plurality of slots which receiverespectively the inner ends of the rocker arms and wherein the frictionmeans each comprise a spring ring surrounding the said inner end of eachof the rocker arms and being in frictional engagement therewith and withthe associated slot.

15. An infinitely variable change speed gear as claimed in claim 13wherein the cam is provided with a plurality of cam slots, there beingfurther provided:

(a) a plurality of guide members carried respectively in the cam slotsand each having a bore in which is received the inner end of anassociated rocker arm, and,

(b) a plurality of resilient members respectively within the said boresin the guide members, each resilient member being in frictionalengagement with the wall of the bore and the inner end of the rocker armreceived therein.

16. An infinitely variable change speed gear of the friction typecomprising:

(a) three coaxial and spaced apart torus discs of which the outer torusdiscs have inwardly facing torus surfaces and the inner torus disc hastwo outwardly facing torus surfaces,

(b) two sets of rollers respectively co-operating with the two facingpairs of torus surfaces,

(0) a plurality of roller carriers carrying said rollers,

(d) a pair of cams, one for each set of rollers, each cam having aplurality of cam slots therein,

(e) a plurality of guide members received respectively within the camslots and being axially movable relative to the cam slots but in adirection inclined to the axis of the torus discs,

(f) two sets of rockers, the rockers being connected respectively to therollers,

(g) an inwardly directed rocker arm carried by each rocker,

(h) a bore in each guide member receiving the inner end of an associatedrocker arm, and

(i) a plurality of friction means respectively acting between the camslots and the guide members to damp axial movements of the guide membersin the cam slots.

17. An infinitely variable change speed gear as claimed in claim 16wherein the friction means comprises a spring embracing a guide memberand bearing against the cam slot to dampen axial movements of the guidemember in the cam slot.

References Cited by the Examiner UNITED STATES PATENTS FOREIGN PATENTS 13 5 France.

DON A. WAITE, Primary Examiner.

1. A INFINITELY VARIABLE CHANGE SPEED GEAR OF THE FRICTION TYPE HAVINGCOAXIALY FIRST AND SECOND TORUS DISCS SPACED APART, A PLURALITY OFROLLERS DRIVABLY CONNECTING THE TORUS DISCS, A TORQUE REACTION MEMBERAND MEANS TO TILT THE AXES OF THE ROLLERS, WHICH MEANS COMPRISES A CAMAND A PLURALITY OF ROCKERS CONNECTED WITH THE ROLLERS AND ALL CONTROLLEDBY THE CAM, SAID ROCKERS EACH BEING PIVOTALLY CARRIED BY THE TORQUEREACTION MEMBER TO PIVOT ABOUT A PIVOT AXIS SUCH THAT THE ROCKER SENSESTHE TORQUE REACTION OF A ROLLER AND THE SAID MEANS TENDS TO BALANCE THETORQUE REACTION OF ALL THE MEANS TENDS TO BALANCE THE TORQUE ROCKER HASAN ARM EXTENDING INTO A CAM AND THE ROCKER ARM WITH RADIAL FREEDOMBETWEEN THE CAM FAN THE ROCKER ARM AND IN THAT AT LEAST ONE OF THE CAMSLOTS CONTINS A GUIDE MEMBER WHICH IS SHAPED TO PERMIT A RELATIVEMOVEMENT AXIALLY OF THE SLOT BETWEEN THE CAM AND THE GUIDE MEMBER AND TOPERMIT RELATIVE ROTATION ABOUT THE AXIS OF THE SLOT BETWEEN THE CAM ANDTHE GUIDE MEMBER BUT TO RETAIN THE GUIDE MEMBER AGAINST RELATIVEMOVEMENT BETWEEN THE CAMF AND THE GUIDE MEMBER AT RIGHT ANGLES TO THEAXIS OF THE SLOT, AND IN THAT THE END OF THE ROCKER ARM EXTENDING INTOTHE SLOT IS RECEIVED WITH FRICTIN IN THE GUIDE MEMBER.